Support of Safety Services through Vehicular Communications: The Intersection Collision Avoidance Use Case

Cooperative systems are based on the periodical exchange of standardized information, thanks to which vehicles can advertise their presence, position and the direction they are moving to, and execute sophisticated C-ITS applications that can detect potentially dangerous situations and properly react. The technological pillar, which must enable a Vehicular ad Hoc Network (VANET), is now being debated: the candidates are the traditional WiFi-based approach and the upcoming cellular one. The application effectiveness, however, depends not only on the technology, but also on how fast it is adopted and becomes widespread, i.e., the so-called technology Penetration Rate (PR). In this paper, simulation is used to evaluate the Intersection Collision Avoidance (ICA) application for both candidate technologies, and evaluated as a function of the technology PR.This work was partially supported by FCA through the DiVe project, by the C.A.R.S. center at Politecnico di Torino, and by the H2020 5G-TRANSFORMER project (Project ID 761536

Vehicular Wireless Communication Standards: Challenges and Comparison

Autonomous vehicles (AVs) are the future of mobility. Safe and reliable AVs are required for widespread adoption by a community which is only possible if these AVs can communicate with each other & with other entities in a highly efficient way. AVs require ultra-reliable communications for safety-critical applications to ensure safe driving. Existing vehicular communication standards, i.e., IEEE 802.11p (DSRC), ITS-G5, & LTE, etc., do not meet the requirements of high throughput, ultra-high reliability, and ultra-low latency along with other issues. To address these challenges, IEEE 802.11bd & 5G NR-V2X standards provide more efficient and reliable communication, however, these standards are in the developing stage. Existing literature generally discusses the features of these standards only and does not discuss the drawbacks. Similarly, existing literature does not discuss the comparison between these standards or discusses a comparison between any two standards only. However, this work comprehensively describes different issues/challenges faced by these standards. This work also comprehensively provides a comparison among these standards along with their salient features. The work also describes spectrum management issues comprehensively, i.e., interoperability issues, co-existence with Wi-Fi, etc. The work also describes different other issues comprehensively along with recommendations. The work describes that 802.11bd and 5G NR are the two potential future standards for efficient vehicle communications; however, these standards must be able to provide backward compatibility, interoperability, and co-existence with current and previous standards

Reducing Message Collisions in Sensing-based Semi-Persistent Scheduling (SPS) by Using Reselection Lookaheads in Cellular V2X

In the C-V2X sidelink Mode 4 communication, the sensing-based semi-persistent scheduling (SPS) implements a message collision avoidance algorithm to cope with the undesirable effects of wireless channel congestion. Still, the current standard mechanism produces high number of packet collisions, which may hinder the high-reliability communications required in future C-V2X applications such as autonomous driving. In this paper, we show that by drastically reducing the uncertainties in the choice of the resource to use for SPS, we can significantly reduce the message collisions in the C-V2X sidelink Mode 4. Specifically, we propose the use of the "lookahead," which contains the next starting resource location in the time-frequency plane. By exchanging the lookahead information piggybacked on the periodic safety message, vehicular user equipments (UEs) can eliminate most message collisions arising from the ignorance of other UEs' internal decisions. Although the proposed scheme would require the inclusion of the lookahead in the control part of the packet, the benefit may outweigh the bandwidth cost, considering the stringent reliability requirement in future C-V2X applications.Comment: Submitted to MDPI Sensor

Heterogeneous LTE/ Wi-Fi architecture for intelligent transportation systems

Intelligent Transportation Systems (ITS) make use of advanced technologies to enhance road safety and improve traffic efficiency. It is anticipated that ITS will play a vital future role in improving traffic efficiency, safety, comfort and emissions. In order to assist the passengers to travel safely, efficiently and conveniently, several application requirements have to be met simultaneously. In addition to the delivery of regular traffic and safety information, vehicular networks have been recently required to support infotainment services. Previous vehicular network designs and architectures do not satisfy this increasing traffic demand as they are setup for either voice or data traffic, which is not suitable for the transfer of vehicular traffic. This new requirement is one of the key drivers behind the need for new mobile wireless broadband architectures and technologies. For this purpose, this thesis proposes and investigates a heterogeneous IEEE 802.11 and LTE vehicular system that supports both infotainment and ITS traffic control data. IEEE 802.11g is used for V2V communications and as an on-board access network while, LTE is used for V2I communications. A performance simulation-based study is conducted to validate the feasibility of the proposed system in an urban vehicular environment. The system performance is evaluated in terms of data loss, data rate, delay and jitter. Several simulation scenarios are performed and evaluated. In the V2I-only scenario, the delay, jitter and data drops for both ITS and video traffic are within the acceptable limits, as defined by vehicular application requirements. Although a tendency of increase in video packet drops during handover from one eNodeB to another is observed yet, the attainable data loss rate is still below the defined benchmarks. In the integrated V2V-V2I scenario, data loss in uplink ITS traffic was initially observed so, Burst communication technique is applied to prevent packet losses in the critical uplink ITS traffic. A quantitative analysis is performed to determine the number of packets per burst, the inter-packet and inter-burst intervals. It is found that a substantial improvement is achieved using a two-packet Burst, where no packets are lost in the uplink direction. The delay, jitter and data drops for both uplink and downlink ITS traffic, and video traffic are below the benchmarks of vehicular applications. Thus, the results indicate that the proposed heterogeneous system offers acceptable performance that meets the requirements of the different vehicular applications. All simulations are conducted on OPNET Network Modeler and results are subjected to a 95% confidence analysis

C-ITS road-side unit deployment on highways with ITS road-side systems : a techno-economic approach

Connectivity and cooperation are considered important prerequisites to automated driving, as they are crucial elements in increasing the safety of future automated vehicles and their full integration in the overall transport system. Although many European Member States, as part of the C-Roads Platform, have implemented and are still implementing Road-side Units (RSUs) for Cooperative Intelligent Transportation Systems (C-ITS) within pilot deployment projects, the platform aspires a wide extension of deployments in the coming years. Therefore, this paper investigates techno-economic aspects of C-ITS RSU deployments from a road authority viewpoint. A two-phased approach is used, in which firstly the optimal RSU locations are determined, taking into account existing road-side infrastructure. Secondly, a cost model translates the amount of RSUs into financial results. It was found that traffic density has a significant impact on required RSU density, hence impacting costs. Furthermore, major cost saving can be obtained by leveraging existing road-side infrastructure. The proposed methodology is valuable for other member states, and in general, to any other country aspiring to roll out C-ITS road infrastructure. Results can be used to estimate required investment costs based on legacy infrastructure, as well as to benchmark with the envisioned benefits from the deployed C-ITS services

An LTE-Direct-Based Communication System for Safety Services in Vehicular Networks

With the expected introduction of fully autonomous vehicles, the long-term evolution (LTE)-based vehicle-to-everything (V2X) networking approach is gaining a lot of industry attention, to develop new strategies to enhance safety and telematics features. The vehicular and wireless industries are currently considering the development of an LTE-based system, which may co-exist, with the IEEE 802.11p-based systems for some time. In light of the above fact, our objective is to investigate the development of LTE Proximity Service (ProSe)-based V2X architecture for time-critical vehicular safety applications in an efficient and cost-effective manner. In this chapter, we present a new cluster-based LTE sidelink-based vehicle-to-vehicle (V2V) multicast/broadcast architecture to satisfy the latency and reliability requirements of V2V safety applications. Our proposed architecture combines a new ProSe discovery mechanism for sidelink peer discovery and a cluster-based round-robin scheduling technique to distribute the sidelink radio resources among the cluster members. Utilizing an OMNET++ based simulation model, the performance of the proposed network architecture is examined. Results of the simulation show that the proposed algorithms diminish the end-to-end delay and overhead signaling as well as improve the data packet delivery ratio (DPDR) compared with the existing 3GPP ProSe vehicle safety application technique

Cellular-V2X Communications for Platooning: Design and Evaluation

Abstract: Platooning is a cooperative driving application where autonomous/semi-autonomous vehicles move on the same lane in a train-like manner, keeping a small constant inter-vehicle distance, in order to reduce fuel consumption and gas emissions and to achieve safe and efficient transport. To this aim, they may exploit multiple on-board sensors (e.g., radars, lidars, positioning systems) and direct vehicle-to-vehicle communications to synchronize their manoeuvres. The main objective of this paper is to discuss the design choices and factors that determine the performance of a platooning application, when exploiting the emerging cellular vehicle-to-everything (C-V2X) communication technology and considering the scheduled mode, specified by 3GPP for communications over the sidelink assisted by the eNodeB. Since no resource management algorithm is currently mandated by 3GPP for this new challenging context, we focus on analyzing the feasibility and performance of the dynamic scheduling approach, with platoon members asking for radio resources on a per-packet basis. We consider two ways of implementing dynamic scheduling, currently unspecified by 3GPP: the sequential mode, that is somehow reminiscent of time division multiple access solutions based on IEEE 802.11p – till now the only investigated access technology for platooning – and the simultaneous mode with spatial frequency reuse enabled by the eNodeB. The evaluation conducted through system-level simulations provides helpful insights about the proposed configurations and C-V2X parameter settings that mainly affect the reliability and latency performance of data exchange in platoons, under different load settings. Achieved results show that the proposed simultaneous mode succeeds in reducing the latency in the update cycle in each vehicle’s controller, thus enabling future high-density platooning scenarios

On the Design of Sidelink for Cellular V2X: A Literature Review and Outlook for Future

Connected and fully automated vehicles are expected to revolutionize our mobility in the near future on a global scale, by significantly improving road safety, traffic efficiency, and traveling experience. Enhanced vehicular applications, such as cooperative sensing and maneuvering or vehicle platooning, heavily rely on direct connectivity among vehicles, which is enabled by sidelink communications. In order to set the ground for the core contribution of this paper, we first analyze the main streams of the cellular-vehicle-to-everything (C-V2X) technology evolution within the Third Generation Partnership Project (3GPP), with focus on the sidelink air interface. Then, we provide a comprehensive survey of the related literature, which is classified and critically dissected, considering both the Long-Term Evolution-based solutions and the 5G New Radio-based latest advancements that promise substantial improvements in terms of latency and reliability. The wide literature review is used as a basis to finally identify further challenges and perspectives, which may shape the C-V2X sidelink developments in the next-generation vehicles beyond 5G

Performance analysis of V2X technologies 802.11p and LTE-PC5

The concept of Digital Twin (DT) has been broadly adopted in the Industry 4.0, in the healthcare and in the Smart Cities. It represents a digital model of the reality where it is possible to test and evaluate different actions before implementing them into the real world. In the context of Smart City, the digital copy of the city includes the representation of the road infrastructure, vehicles, pedestrians, .... Its main objectives are to ease the road maintenance, to provide the means for mobility simulations, and to create traffic information management systems. This prNowadays, Vehicular-to-Everything (V2X) communications are becoming an essential element to improve safe driving conditions and autonomous driving. This thesis presents a comparison of two V2X communication technologies: IEEE 802.11p, and Cellular-V2X. The objective of this study is to evaluate the performance of both technologies in terms of the Medium Acces Control (MAC) layer, especially in a congested environment. Therefore, we analyze the different schemes used on these technologies to access shared channel resources and avoid interferences. The study is conducted using several simulation tools: SUMO which allows us to create personalized scenarios, and OMNeT++ used to simulate the network and transmit all the V2X messages between the vehicles. With SUMO we created a highway scenario that can support a high density of vehicles. And OMNeT++ is used to change the main simulation parameters, and obtain results such as all the packets received and sent through the network. Finally, we defined some performance metrics to analyze the results and observe how the technologies react over a congested scenario, with high densities of vehicles